Membranous nephropathy is a common cause of nephrotic syndrome. About 15% of membranous nephropathy cases are secondary membranous nephropathy, caused by drugs, infections, tumors, immune diseases. The remaining 85% of membranous nephropathy cases are idiopathic, also called autoimmune primary membranous nephropathy. Its origin remains unknown. About one half of patients with idiopathic membranous nephropathy who did not receive treatments will develop end-stage renal disease requiring dialysis or renal transplantation. Among the kidney transplants, about 40% of them will relapse.
PLA2R1 has been described as a major autoantigen in idiopathic membranous nephropathy and can be used for the diagnosis and monitoring of treatment of idiopathic membranous nephropathy both before and after kidney graft. Possible therapeutic strategies based on this autoantigen have also been reported.
However, only about 70% of patients suffering from idiopathic membranous nephropathy have anti-PLA2R1 autoantibodies, suggesting that other autoantigens and corresponding autoantibodies may be involved in the remaining 30% cases. Thus, there is a corresponding need for diagnosis, prognosis and theragnosis for the 30% of patients who cannot be followed based on the PLA2R1 autoantigen.